Advanced Materials Research Vols. 756-759

Abstract: Al-based coating on ZM5 magnesium alloy was prepared by Supersonic Particles Deposition (SPD). Electrochemical working station was utilized to test polarization curve, corrosion potential and electrochemical impedance spectroscopy etc. The results indicted that corrosion potential of Al-Si coating was about-767.6mV, much higher than that of ZM5 Mg-substrate; And corrosion current density of the coating sample decreased three order of magnitude than that of the uncoated. Compared to Mg-substrate, the radius of capacitive impedance arc of the coating enlarged and impedance modulus improved two order of magnitude.

Abstract: Cu-matrix bearing materials were prepared by powder metallurgy method and their mechanical properties were studied in present work. The continuity of copper alloy matrix was destroyed with the increase of Bi element. Because Bi is brittle phase and distributed in the copper alloy matrix grain boundaries as thin ribbon network. The hardness, crushing strength and impact toughness of copper-bearing materials were reduced with increase of the content of Bi. The mainly of Copper-bearing materials containing bismuth fracture are brittle intergranular fracture. When the Bi content is over 4wt%, the Bi has a relatively full distribution in the rich Bi phase of copper alloy matrix grain boundary like a chip mesh belt. As the further increase of Bi, the reduced trends of the mechanical properties of Cu-matrix bearing materials containing bismuth are slow down. because the role of fragmented Copper alloy matrix will not significantly increase with further increase of Bi.

Abstract: The effect of elastic stress on the precipitation process of 7075 Al alloy aged at 438 K for 1 hour has been investigated in this paper. The mechanical properties have been measured by hardness testing and scanning electron microscopy (SEM) and the microstructures have been characterized by optical microscopy (OM), together with transmission electron microscopy (TEM). Results indicate that the microhardness can reach 180 HV after a 25 MPa elastic tensile stress aging treatment, much higher than the stress-free ones'. The fracture is more brittle and the formation of the precipitates is promoted in the case of the stress-aged specimen. Our study provides a new process to bring down the energy consumption.

Abstract: Purification and antioxidation of glycosaminoglycan from Patinopecten yessoensis waste were studied. The results showed that the glycosaminoglycan contained characteristic functional groups like-OH(3424cm^-1), -COO-(1653cm^-1) and-NH(1567cm^-1), -SO₂(1414 cm^-1), C-O-C(sugar ring,1044cm^-1),, and it had good ability of scavenging DPPH free radicals and reducibility as well as metal chelating.

Abstract: Composition of an AlGaAs/GaAs/Ge triple-junction solar cell were analyzed using an equivalent circuit. The currentvoltage (IV) characteristics and impedance spectroscopy (IS) of it were measured in the temperature range from 20°C to 180°C. In the high-temperature range (from 140°C to 200°C) the V_OC changes faster than those in the low-temperature range (from 20°C to 80°C).This is because contribution of the V_OC from the Ge subcell becomes nearly zero in the high temperature. R and C of the bottom subcell keep almost the same in the high temperature.

Abstract: A statistical model is proposed for the analysis of fatigue crack propagation, based on the theory of fracture mechanics and stochastic process. The fatigue growth process is approximated as a diffusive Markov process. The associated backward Fokker-Plank equation and boundary conditions are written, and the distribution of crack propagation time under a given crack size is obtained by using an Eigenfunction method. The sought distribution is expressed in the form of a convergent infinite series. An examples is presented to illustrate the application of the method. The predicted results seem to agree with the experimental data.

Abstract: nanosized copper thin film was prepared on glass substrates by magnetron sputtering. 800 nm pump and 400nm probe technique were used to measure time-resolved reflectivity of copper thin film, and the heat transport processes of copper film were experimentally studied. Thermal transport processes in the copper film were numerically simulated by using Parabolic Two-Step (PTS) model with Finite Difference method. The result of the PTS model can well evaluate the measure date.

Abstract: This paper studies on the stability capacity of E-glass fiber reinforced polymer (GFRP) tubes under axial compression in order to get the formula, which can be applied to structure design. Firstly, on the basis of test data, finite element analysis is carried out and initial geometric imperfection is considered in the models. Then, it's proved that edge-failure criterion is suitable for stability analysis of GFRP slender components by comparison of results derived from several classic formulas. Finally, a modified Perry-Robertson stability formula is proposed so as to ascertain corresponding stability coefficients for GFRP tubes with different slenderness ratio.

Abstract: 2A12 alloy by MAO on main salts electrolyte system of phosphate sodium is investigated. By contrast test, the influences of arc starting voltage, the thickness of the ceramic layer , growth rate, and wear resistance with different K₂Cr₂O₇ concentration are analyzed. If K₂Cr₂O₇ concentration is 2.5g/L , the arc starting voltage reached the lowest, the surface topography is the best, the wear resistance is the well.

Abstract: Currently, the SCC is already used in several countries and is considered a breakthrough in the building process of concrete structures, as it increases productivity, reduces the demand for labor, work in time of concreting and improves the quality of the concrete and the environment work. Innumerous investigations on SCC [,[,[,[ have been developing in order to know their behavior, improve their properties and applicability in different structural elements. This paper presents the implementation of the SCC in the execution of the base of the waters reservoir, in water treatment station.